The point is that instead of having to use the nose mounted radar at full power 20kW beam strength scanning its entire volume of frontal air space looking for a needle in a haystack, you can use the wing mounted radar elements to scan rapidly without needing enormous power levels in a frequency most enemy aircraft can't even detect, and if they do it is non directional detection so they know the signal is being beamed but can't tell where it is coming from... imagine an AM radio scanning and scanning but never detecting the signals from FM radio stations because they operate on a different frequency.
Once the wing mounted arrays detect a solid return where your nose mounted radar did not detect anything very much, or just got a very weak return, then the pilot and the aircraft will know there is something there and that IRST and nose mounted super powerful AESA radar could scan that area in much more detail to detect any weak returns and therefore a stealthy target.
More importantly a flight of Su-35s and Su-57s and S-70s can all use their radar to listen in that direction too while one of them scans in their nose mounted AESA radar (Ku and Ka band) and also perhaps wing mounted L band frequencies.... the return signals should be enough to determine if there is actually something there and where it actually is in terms of altitude and distance...
Ground based radar should also be able to provide information and ground based radar listening to these radar pulses might also contribute to finding these stealthy targets and let them mount attacks against them.
The new PAK DA is a flying wing and will carry AAMs, so there is probably a good chance it will have rather bigger wing leading edge mounted radar... the brand new technology photonic radar will be surface mounted and therefore could be located on the leading edge of the wings and fuselage sides for 360 degree scanning and it operates in Terahertz frequencies which would probably render stealth useless anyway.
Is it an 8-brick AESA radar? Does it have its own cooling system since I would think that is a very important aspect for it since all the friction on the leading edge flaps and wings would greatly affect it, especially if Egypt has ordered 30 fighters and the heat in Egypt is unimaginable in mid-summer.
I would think it would be fairly heat resistant, and that the location would mean airflow could be used for cooling most of the time... it is not an IR system so it can operate hot.
In that case, is it limited to higher altitudes where the air is less denser and cooler creating more optimal uses? Is it limited to certain lower speeds because of cooling? Or is it capable of being used at any time and altitude?
I would think it does not operate at enormous energy levels and the large size of the elements will further reduce the heat generation... for the nose mounted high frequency radar having small elements that can pump out 20kW signals... that is eye watering stuff... so much that I might be mistaken.... most electric element heaters are 2kW, and normally have three or four bar elements to generate that sort of heat, so ten times more power in a radar element a cm across or less sounds like a lot to me.
The L band wing mounted radar wont need anything like that level of power... it does not rely on power to detect targets, it relies on the fact that the frequency is so long it does not detect shape so the complex stealthy shaping of a B-2 or F-22 intended to redirect the radio waves away from its source don't work because the waves are not effected by shape so the whole aircraft reflects the signal at normal ranges...
How affective is the range? I'm hearing numbers like 200km and others at 100 to 150?
I have never seen actual numbers mentioned, but the inference is that detection range in L band is the same for stealthy and non stealthy targets, so the distance you could detect an F-15 or B-1B is the same as for the F-22 and B-2... the problem is that detecting the target again with another sensor to allow you to then track it might mean it can only be tracked at shorter ranges.
Having ground based radar that can also detect stealthy targets like the NEBO system would mean the ground based system might detect the stealth aircraft first and send the Su-35s to intercept... they could initially use their wing mounted radar to indicate where the target is and then zero in on it till they can detect it with other sensors too and start to open fire.
Note NEBO has several very different frequency radar which each scan in different frequencies... imagine it to be like using a microphone and binoculars and a thermal imager and a ground radar. Each has a useful frequency range but each also has limitations and restrictions. Binoculars need clear days and do not work at night, microphone can detect noise which can cue you to look in a direction before the target is even visible, a thermal sight can see through smoke and dust and at night but it is not so easy to identify things, and radar is excellent in terms of range and detecting movement.
Individually the compliment each other but add a computer processing power and together they can build up a view of the space around you showing different sounds and visible and non visible things as detected by the different sensors. They can be used to direct your binoculars towards something that you can then direct a powerful beam of light towards so you can visually identify a target that would otherwise have flown in a pattern to avoid a scanning beam of light.
Low light level digital TV is getting to the point where it can see in the dark too without all the problems of Image intensification and short sensor life.
NEBO combines the signals of long and short wave radar to get extra information and to eliminate the problems of long wave and short wave radar and just provide much better information.
I would expect Sukhoi are doing the same with their sensors with different radar and EO sensors that can be carried.